Package org.apache.commons.collections4.functors

This package contains implementations of the Closure, Predicate, Transformer and Factory interfaces. These provide simple callbacks for processing with collections.

WARNING: from v4.1 onwards several unsafe classes in this package will not be serializable anymore in order to prevent potential remote code execution exploits.

Classes considered to be unsafe are:

• CloneTransformer
• ForClosure
• InstantiateFactory
• InstantiateTransformer
• InvokerTransformer
• PrototypeFactory$PrototypeCloneFactory
• PrototypeFactory$PrototypeSerializationFactory
• WhileClosure

Interface Summary

Interface	Description
PredicateDecorator<T>	Defines a predicate that decorates one or more other predicates.

Class Summary

Class	Description
AbstractQuantifierPredicate<T>	Abstract base class for quantification predicates, e.g.
AllPredicate<T>	Predicate implementation that returns true if all the predicates return true.
AndPredicate<T>	Predicate implementation that returns true if both the predicates return true.
AnyPredicate<T>	Predicate implementation that returns true if any of the predicates return true.
CatchAndRethrowClosure<E>	Closure that catches any checked exception and re-throws it as a FunctorException runtime exception.
ChainedClosure<E>	Closure implementation that chains the specified closures together.
ChainedTransformer<T>	Transformer implementation that chains the specified transformers together.
CloneTransformer<T>	Transformer implementation that returns a clone of the input object.
ClosureTransformer<T>	Transformer implementation that calls a Closure using the input object and then returns the input.
ComparatorPredicate<T>	Predicate that compares the input object with the one stored in the predicate using a comparator.
ConstantFactory<T>	Factory implementation that returns the same constant each time.
ConstantTransformer<I,O>	Transformer implementation that returns the same constant each time.
DefaultEquator<T>	Default Equator implementation.
EqualPredicate<T>	Predicate implementation that returns true if the input is the same object as the one stored in this predicate by equals.
ExceptionClosure<E>	Closure implementation that always throws an exception.
ExceptionFactory<T>	Factory implementation that always throws an exception.
ExceptionPredicate<T>	Predicate implementation that always throws an exception.
ExceptionTransformer<I,O>	Transformer implementation that always throws an exception.
FactoryTransformer<I,O>	Transformer implementation that calls a Factory and returns the result.
FalsePredicate<T>	Predicate implementation that always returns false.
ForClosure<E>	Closure implementation that calls another closure n times, like a for loop.
IdentityPredicate<T>	Predicate implementation that returns true if the input is the same object as the one stored in this predicate.
IfClosure<E>	Closure implementation acts as an if statement calling one or other closure based on a predicate.
IfTransformer<I,O>	Transformer implementation that will call one of two closures based on whether a predicate evaluates as true or false.
InstanceofPredicate	Predicate implementation that returns true if the input is an instanceof the type stored in this predicate.
InstantiateFactory<T>	Factory implementation that creates a new object instance by reflection.
InstantiateTransformer<T>	Transformer implementation that creates a new object instance by reflection.
InvokerTransformer<I,O>	Transformer implementation that creates a new object instance by reflection.
MapTransformer<I,O>	Transformer implementation that returns the value held in a specified map using the input parameter as a key.
NonePredicate<T>	Predicate implementation that returns true if none of the predicates return true.
NOPClosure<E>	Closure implementation that does nothing.
NOPTransformer<T>	Transformer implementation that does nothing.
NotNullPredicate<T>	Predicate implementation that returns true if the input is not null.
NotPredicate<T>	Predicate implementation that returns the opposite of the decorated predicate.
NullIsExceptionPredicate<T>	Predicate implementation that throws an exception if the input is null.
NullIsFalsePredicate<T>	Predicate implementation that returns false if the input is null.
NullIsTruePredicate<T>	Predicate implementation that returns true if the input is null.
NullPredicate<T>	Predicate implementation that returns true if the input is null.
OnePredicate<T>	Predicate implementation that returns true if only one of the predicates return true.
OrPredicate<T>	Predicate implementation that returns true if either of the predicates return true.
PredicateTransformer<T>	Transformer implementation that calls a Predicate using the input object and then returns the result.
PrototypeFactory	Factory implementation that creates a new instance each time based on a prototype.
StringValueTransformer<T>	Transformer implementation that returns the result of calling String.valueOf on the input object.
SwitchClosure<E>	Closure implementation calls the closure whose predicate returns true, like a switch statement.
SwitchTransformer<I,O>	Transformer implementation calls the transformer whose predicate returns true, like a switch statement.
TransformedPredicate<T>	Predicate implementation that transforms the given object before invoking another Predicate.
TransformerClosure<E>	Closure implementation that calls a Transformer using the input object and ignore the result.
TransformerPredicate<T>	Predicate implementation that returns the result of a transformer.
TruePredicate<T>	Predicate implementation that always returns true.
UniquePredicate<T>	Predicate implementation that returns true the first time an object is passed into the predicate.
WhileClosure<E>	Closure implementation that executes a closure repeatedly until a condition is met, like a do-while or while loop.

Enum Summary

Enum	Description
ComparatorPredicate.Criterion